too slow

my jawa was doing around 22mph flat ground last week(which i don't think is as fast as it should be going) but this week when i rode it, it was only doing about 17ish mph...i have heard that a clogged muffler may slow it down, but i'm not sure how to un-clog a muffler, also will it hurt the moped if i drive it with the muffler off? i'm not planning on doing it often but i just wanted to see if it would run faster with it off or if the muffler was the problem at all


Re: too slow

it wont hurt to test with no muffler, but it won't prove anything either .. i can almost guarantee it'll have faster top speed.

there's lots of threads about cleaning mufflers (Search) and may be something in the Jawa owner's manual on THIS page break>

btw, regarding your air filter question, that manual shows a couple different carbs on Jawas. At least one has a small internal air filter, probably a screen, while the empty air-box is a protective, intake-roar muffler.. So what type of carb do you have?

Re: too slow

i'm not sure what the carb is...IKOV maybe?

do you have any other suggestions as to why it would be going so slow? and it barely went faster with the muffler off...i know you said that would prove anything but i tried it for shits and grins

Re: too slow

other than a clogged muffler, is there anything else that would slow the moped down so much?

Re: too slow

i dunno anything spcific about your bike so all i can offer is genral suggestions ..

if the engine reaches normal top RPM but the bike is slow, mayb be a slipping clutch .. wrong tranny fluid or low fluid level or related..

of course there's dragging brakes .. flat tire.. belt slipping if it's belt drive due to dirty or grease slicked pulleys or belt..

engine weakness can be due to a lot of things.. weak ignition causes misfires .. carb trouble causes wrong air:fuel mix and also causes misfires .. air leaks in or around the cylinder / intake gaskets (torque head bolts and tighten everything). Intake air restriction .. badly worn piston rings.. high friction due to lack of oil..

it goes on and on .. i recommend a thorough tune up starting from scratch .. check the bike from end to end. Read the manual and read FREDs GUIDE on top of that page.

Re: too slow

If your muffler was clogged you would be able to tell just by the sound... it would go from a clean putting/popping sound to a hum like a tired Hoover vacuum cleaner lol...

Check out the obvious things first.. air flow through the air cleaner... fuel flow to the carb...throttle cable pinched.. or stuck on choke... something of that nature...

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